Wikipedia:Reference desk/Archives/Science/2012 April 18

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April 18

Identify the monkeys

What is the species of these monkeys?

Looks a bit like a rhesus macaque, except for the dark faces and ears. StuRat (talk) 04:34, 18 April 2012 (UTC)

As can be seen from the photo, young monkeys of this species don't have dark face, but their face becomes dark when they mature. --SupernovaExplosion ^Talk 04:36, 18 April 2012 (UTC)

Here's some more pics of rhesus macaques, and the top one has a bit darker face, getting closer to those in the pic: [1]. StuRat (talk) 04:48, 18 April 2012 (UTC)

I think they are langurs. going by the black face, body shape and loong tail.Staticd (talk) 05:20, 18 April 2012 (UTC)

Yes, that's right, specifically the black-faced, long-tailed langur monkey: [2], [3]. StuRat (talk) 05:31, 18 April 2012 (UTC)

Thanks for the links! So these are gray langurs. But which species? --SupernovaExplosion ^Talk 06:57, 18 April 2012 (UTC)

Northern plains gray langur, although "gray" seems a bit of a misnomer, since they are rather brown. StuRat (talk) 07:20, 18 April 2012 (UTC)

Which water is better for boiling and drinking, water from toilet tap or water from kitchen tap?

--58.251.146.129 (talk) 04:55, 18 April 2012 (UTC)

There is no advantage to using toilet water at all. Toilet valves don't have the same health restrictions on metal composition that kitchen taps do. 71.212.237.94 (talk) 05:22, 18 April 2012 (UTC)

Assuming that the water comes from the same water supply, and that there is no difference between the plumbing from the point that the bathroom and kitchen lines diverge, then they are both equivalent. I don't know what "health restrictions" 71.212.237.94 is referring to, but there will be no significant amount of toxic metals leached into the water from a tap regardless of whether it is from the kitchen or the bathroom. It just isn't in contact with the surface of that metal for long enough, and if the metal was readily entering solution, the tap would corrode to the point of needing replacing in a very short period. I don't know of any design differences that could make any one of them more hygenic than the other as they appear to be essentially equivalent, and for the most part interchangeable fixtures. I do agree that there is no advantage (other than perhaps being thirsty near the bathroom and too lazy to go to the kitchen.Though you'd probably have to go to the kitchen to boil it anyway...). 203.27.72.5 (talk) 05:32, 18 April 2012 (UTC)

One diff is that kitchen taps often have a faucet aerator with screen, which bathroom taps lack. So, I'd go with the kitchen tap, since it's more likely to filter out sharp chunks of metal. StuRat (talk) 05:36, 18 April 2012 (UTC)

My bathroom tap also has this. Many (most?) people routinely put bathroom tap water into their mouths when brushing their teeth, so the faucet must be designed with this in mind. 203.27.72.5 (talk) 06:29, 18 April 2012 (UTC)

It's not like toxic waste comes out of the bathroom tap, but those lacking a screen are more likely to deposit the occasional chunk of debris. StuRat (talk) 06:54, 18 April 2012 (UTC)

Citation? I've used taps for a long time and never seen an "occasional chunk of debris," certainly never had the possibility of ingesting "sharp chunks of metal." Until I see a citation I am filing this under "bizarre things StuRat worries about but nobody else does," which is a fairly long list at this point. ;-) --Mr.98 (talk) 14:18, 18 April 2012 (UTC)

Here: [4]. I seem to get the Black Particles here, but the metal ones tend to be rusty (see the Brown or Orange Particles section). If you had a screen, you might find you need to periodically clean it when water starts spraying out at odd angles. Without a screen, you might just be ingesting these particles. StuRat (talk) 18:49, 18 April 2012 (UTC)

According to your link; "They...are not a health hazard". Handschuh-^{talk to me} 22:38, 18 April 2012 (UTC)

I didn't say they were (but biting down on a piece of rusted metal does seem to present some health risks). StuRat (talk) 01:58, 19 April 2012 (UTC)

Am I the only one reading this as "Is there a difference between the water in the toilet (cistern or bowl) and the water from the kitchen faucet"? Is "toilet tap" a common name for the faucet in one's bathroom/loo/etc? Dismas|^(talk) 05:56, 18 April 2012 (UTC)

Your confusion springs from their use of British English, where "toilet" = "bathroom" and "water closet" or "WC" = "toilet". Of course, it's not as bad as if they said "I just washed my hands in the toilet". StuRat (talk) 05:59, 18 April 2012 (UTC)

The IP seems to be in Shenzhen so I think the answer might be neither until later this year. Sean.hoyland - talk 06:14, 18 April 2012 (UTC)

To whose IP do you refer and what happens later this year ? StuRat (talk) 06:24, 18 April 2012 (UTC)

The OP 58.251.146.129 and Shenzhen being able to provide potable water from city taps by the second half of 2012. Sean.hoyland - talk 06:30, 18 April 2012 (UTC)

Well, my confusion is actually two-fold. First there's the confusion of whether "toilet" refers to a room or a device. And second, there's the mention of boiling the water. I don't normally boil water from any source in my home unless I intend to cook with it. Therefore, I thought they introduced the boiling aspect because they were referring to drinking water from the toilet device. Dismas|^(talk) 06:29, 18 April 2012 (UTC)

In many localities (such as where I live in Indonesia), tap water is not considered drinkable unless you boil it first. Shenzhen's tap water may be of similar quality. I speak Australian English natively, and I wouldn't refer to the bathroom as the toilet, but I gathered from the context what the OP meant. 203.27.72.5 (talk) 06:33, 18 April 2012 (UTC)

In many older houses and other buildings in the UK, the kitchen tap is fed directly from the incoming supply, whereas the other taps in the building are often fed from a header tank in the loft. I never drink from other taps in public buildings since I found one with dead pigeons in the header tank! There are some toxins that are not eliminated by boiling, but these are comparatively rare. Dbfirs 07:45, 18 April 2012 (UTC)

Agree with D, the standard in the UK is for mains water to be drinkable, and a mains water supply goes directly to the kitchen cold water tap for drinking and cooking purposes. Many buildings have a cold water storage tank in the loft which is fed by the mains water supply, and in turn supplies water to the taps in other rooms, such as toilets. The tank also feeds a hot water cylinder which feeds hot water taps. The cold water storage tank should have a lid on it to prevent debris or dead animals contaminating the supply, but lids weren't always fitted and may not give full protection. The very fact of the water being stored in this way makes it questionable, though it should usually be safe to drink.
In more recent systems (not sure if this applies in all areas) mains water is supplied to all the cold taps, and also to the hot taps where a combi boiler is fitted to heat the water when required, rather than storing hot water in a cylinder.
The systems will vary in other countries, as will the advisability of boiling water for drinking. . dave souza, talk 08:25, 18 April 2012 (UTC)

well, I mean just toilets in our homes. Is it true that there could be more bacteria in bathroom tap like any other thing in the bathroom?--58.251.146.129 (talk) 10:36, 18 April 2012 (UTC)

There are bacteria on nearly every surface, and the human body is more than 90% bacteria by cell count (see Human microbiome) You are less than 10% human! Most bacteria are harmless, and some are beneficial -- bacteria are our ancestors! You probably breathe in more bacteria on a visit to the bathroom than you will pick up from the bathroom tap -- bacteria tend to dislike metal, though I suppose there is the possibility of a colony developing in a dirty tap. I'd be more worried about the source of the water than the way in which it is delivered. Dbfirs 12:26, 18 April 2012 (UTC)

Interesting. What is used in other countries then instead of the header tank? Also I think I now know where the thing about not drinking from the hot water tap because it is "spider water" may have come from. CambridgeBayWeather (talk) 13:06, 18 April 2012 (UTC)

What is a header tank? Wikipedia doesn't seems to know (although some articles mention household heating oil header tanks and auto and plane radiator header tanks). Is a water header tank necessary because of low water pressure? Rmhermen (talk) 13:32, 18 April 2012 (UTC)

It is a water tank, usually in the loft, with a ball cock, fed by mains water supply and supplying water to wash basins, baths, showers and toilets in the house by gravity feed. Main advantage is it provides a temporary water supply if mains water supply is interrupted. Gandalf61 (talk) 16:21, 18 April 2012 (UTC)

I would think the cost of the extra plumbing, tank and reinforcment to house framing to handle the weight would be more expensive than the minor advantage most places. I live in an area supplied by the less-than-stellar Detroit water system but have only lost water once in 15 years - during the Northeast blackout of 2003. Rmhermen (talk) 17:32, 18 April 2012 (UTC)

Actually, the main purpose is that the height of the tank above the bathroom/toilet provides some pressure to the taps. In some areas the mains pressure gives a good flow in the kitchen at ground floor but rather less at the first floor. SpinningSpark 17:48, 18 April 2012 (UTC)

Also in Detroit here, but we didn't lose water in the 2003 blackout. The water quality and pressure are also quite good here, although we do get the occasional "boil water" warning after the annual "water main breaking festival", each winter (we seem to have avoided them this winter, due to mild weather). So, the only water tanks in the house are the hot water tank and each toilet tank. StuRat (talk) 18:44, 18 April 2012 (UTC)

More generally, a header tank is any tank that stores the fluid you want to pump at a height above the point where you want to pump it, that is, it provides head pressure. They have many applications where the constant force of gravity gives a smooth flow even if the pump you're using to move the water doesn't (e.g. diaphragm pump). We use them in industrial plants to provide a smooth flow of copper sulphate and other reagents to the continuous processes that need them. 1.142.75.214 (talk) 19:46, 18 April 2012 (UTC)

In the US, we tend to use elevation differences to feed water from elevated reservoirs, and water towers to supplement these, rather than tanks in each house. StuRat (talk) 20:54, 18 April 2012 (UTC)

In Australia rain water tanks are becoming very common and are compulsory for new houses in some areas. My parent's house actually has three old liquid reagent bulk boxes plumbed in to take the water from the downpipes, which is what you get when you come from a family of chemical engineers. 203.27.72.5 (talk) 21:23, 18 April 2012 (UTC)

But water collected like that would be unsafe to drink, without boiling or treated in some other way. After all, your roof is hardly sanitary. StuRat (talk) 21:36, 18 April 2012 (UTC)

My parents only use their rain water for the garden and the pool, but other people do drink theirs. In monsoonal areas it rains so frequently during the wet season that anything that will be moved off your roof by rain water is gone after a couple of showers. For that reason, the first few days worth of water is used as grey water, and after that it can be consumed. Of course dead animals or bird faeces may be on there too, but that's not likely to do you any great harm (from the wikipedia article on rain water tank; "reports of illness associated with rainwater tanks are relatively infrequent, and public health studies in South Australia (the Australian state with the highest rainwater usage rate) have not identified a correlation"). You want to look at what happens to tap water before it reaches your house even in first world countries. It's usually sourced from lakes or rivers (that contain wildlife and its waste), screened, receives a tiny dose of chlorine and fluoride, then pumped to your house. Many people use inline water filters for their drinking rain water, but many do not. Handschuh-^{talk to me} 22:28, 18 April 2012 (UTC)

In the western United States, rainwater tanks can be illegal: because of the way water rights laws work, the rainwater you're retaining may belong to someone else. --Carnildo (talk) 23:05, 18 April 2012 (UTC)

I'd like to see a citation for that. I find it hard to believe that they could pass a law against you gathering rainwater that landed on your own property. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:52, 19 April 2012 (UTC)

Why not? They've passed laws that make it illegal to gather minerals from your own land. Handschuh-^{talk to me} 02:42, 19 April 2012 (UTC)

I'm not quite seeing that in the article. But isn't there some sort of rule about how "deep" your property goes? That is, it doesn't go all the way to the center of the earth. In any case, I would still like to see a citation for a law that says you can't put a rain barrel on your property. ←Baseball Bugs ^{What's up, Doc?} carrots→ 03:36, 19 April 2012 (UTC)

Depends on the juristdiction obviously, but more on the water situation in the wild west can be found in the article on prior-appropriation water rights. In Australia, all economic minerals in nature belong to the crown and you have to obtain a mining licence and mining lease, and pay royalties to extract them. See Australian mining law. 203.27.72.5 (talk) 04:22, 19 April 2012 (UTC)

And yes there is a rule in common law on how deep your property goes. It's called "whoever owns the soil, it is theirs all the way up to Heaven and down to Hell". 203.27.72.5 (talk) 04:27, 19 April 2012 (UTC)

It's right there in Rainwater tank#Colorado law. --Carnildo (talk) 02:17, 21 April 2012 (UTC)

capillary waves

i have a question in my text book that reads:what is the minimum velocity with which capillary waves may travel on the surface of the liquid,surface tension of the liquid=760N/m. I thought a little bit about transverse waves and the formula v=(T/m) but with no help,your help would be appreciated27.4.131.64 (talk) 08:00, 18 April 2012 (UTC)

Capillary waves covers this, though the explanation may be a bit hard to follow (perhaps your text book is better?). Waves on the surface of a liquid are subject to two restoring forces, the downward force of gravity and the surface tension which resists curvature. The former is most important for large wavelengths (the gravity wave regime), and the latter is most important for small wavelength (the capillary wave regime). Because of the interaction of these two effects there is a minimum velocity at which waves can travel on the surface of a fluid. The capillary waves article actually gives the formula for finding the critical wavelength at which the minimum speed occurs, though you'd still have to translate that wavelength into the actual velocity. Dragons flight (talk) 19:46, 18 April 2012 (UTC)

how is this safe

http://imgur.com/2rAEL or even, possible? --80.99.254.208 (talk) 09:55, 18 April 2012 (UTC)

Photoshop. 101.172.255.241 (talk) 10:02, 18 April 2012 (UTC)

I'm gonna say it's not Photoshop. There appears to be a button or cap on the top of the orb which could have been used to fill the orb with water and fish. Or if that is just part of the background then the orb could have been put on with the man upside down and then the collar attached to form a watertight seal. Either way, to answer the original question, I don't see how it's particularly dangerous. Dismas|^(talk) 10:05, 18 April 2012 (UTC)

I see there is something over his nose which stops water from entering nasal cavity. Agree with Dismas, it does not look dangerous. At least far more safe than going underwater as divers do. --SupernovaExplosion ^Talk 11:16, 18 April 2012 (UTC)

I guess the dangerous part, if there was one, is if the intake got clogged (either accidentally or on purpose), how hard would it be to evacuate the bowl? (One can probably just lift it off, in a pinch.) The difference between it and divers going underwater is that there generally speaking aren't a lot of miscellaneous and anonymous jerks under water (sharks being an important exception). --Mr.98 (talk) 14:13, 18 April 2012 (UTC)

Perhaps the questioner is concerned for the safety of the fish. 71.212.237.94 (talk) 16:06, 18 April 2012 (UTC)

As you can see from the photo, the view through the fish bowl is highly distorted. This increases the chance that the wearer will trip up when walking. In doing so, his mouth may loose its grip on the breathing tube and he would need to evacuate the water from the bowl in a very short amount of time to avoid drowning. I think the safety would mainly depend on how quickly the bowl could be evacuated in such an emergency and how firmly the mouth piece is seated. 1.142.75.214 (talk) 19:50, 18 April 2012 (UTC)

There might not be a tight seal around the bottom, in which case just opening the plug on the top to release the pressure would be enough to cause the water to rush out. He would have at least a couple of minutes before he drowned anyway. That is plenty of time to get the water out. --Tango (talk) 20:21, 18 April 2012 (UTC)

So far the only safety risk considered has been drowning. What about infection, from exposure to goldfish feces ? I picture them floating into his ears, for example. StuRat (talk) 20:51, 18 April 2012 (UTC)

There's also the briefly mentioned increased risk of tripping over or running into things. 203.27.72.5 (talk) 21:05, 18 April 2012 (UTC)

Our view along a shallow chord of the fishbowl is distorted, but the wearer's lines of sight are much nearer perpendicular to the surfaces of the bowl and thus less refracted. I imagine the distortion for him is comparable to that caused by eyeglasses for severe myopia. —Tamfang (talk) 22:13, 19 April 2012 (UTC)

He's basically just snorkeling in a very tiny sea. It wouldn't be any more dangerous than snorkeling -- quite a bit less, probably. Looie496 (talk) 20:56, 18 April 2012 (UTC)

What some folks do, to appear eccentric. Goldfish are "dirty" fish, but otherwise harmless. Now, if he had piranhas in there, it could make things more interesting. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:50, 19 April 2012 (UTC)

Aren't piranhas a touch larger? He'd need a bigger tank. --Ouro (blah blah) 19:14, 19 April 2012 (UTC)

Eventually. But their young are much smaller. They just get bigger as they eat more. More goldfish, for example. That might be more action than the fishbowl wearer wants to see near his face, though. ←Baseball Bugs ^{What's up, Doc?} carrots→ 07:11, 20 April 2012 (UTC)

conker tree

How much pruning can a conker tree take? Could it cut right down to the main trunk and still grow?

The genus Aesculus can easily withstand moderate to heavy pruning in the "normal" range. "cutting it down to the main trunk" is not what I'd call normal pruning. The key issue is whether you leave the plant with any meristems after pruning. These are the source of all growth in plants, and, while some species can generate new meristematic tissue from stem cells, it is not usually a good idea to remove all meristems. On the other hand, trees in this genus usually put out many suckers. In principle, if there are suckers at the base, you could remove the entire trunk, and in a few years you'd have dense, shrubby growth. If you want something tree-like at the end, you'll have to repeatedly thin the suckers to keep only a single new trunk growing strongly. With a little practice, you can identify meristems, and prune just beyond them. Lastly, you may be interested in pollarding, which is the practice of removing everything but the main trunk, for the purpose of harvesting good usable branches every few years. This link to the Royal Horticultural Society [5] implies that Conkers are indeed commonly pollarded. So, after all that, I think the answers to your questions are "a lot", and "in principle yes", but of course if the tree is important to you, check with your local arborist :)SemanticMantis (talk)

They can take A LOT of pruning, and often all branches are removed leaving only the main trunk with a club-like head on it from which new braches grow (pollarding to the extreme). It's a common practice in Europe, not only with horse chestnuts, but with willow trees as well. Historically, this was done (with willows, at least) to provide lots of thin braches for basketmaking and house construction (see Wattle and daub). Now it's apparently done for esthetic reasons. I don't quite see the appeal in it, probably because this was my dad's method for pruning just about any tree we had on our property, much to our dismay. Dominus Vobisdu (talk) 23:01, 18 April 2012 (UTC)

Horse chestnuts will coppice, in other words, you can chop the whole tree down and the stump will sprout. The majority of temperate hardwoods will do it too. The unrelated Sweet Chestnut is still coppiced commercially in the south of England, to make fence palings [6] Alansplodge (talk) 23:34, 18 April 2012 (UTC)

preserving seeds

How many years could a conker seed be preserved for and still be growable? I heard about that seed volt in the artic, so there must be a way to perserve them. Would putting them in the freezer do the trick?

Probably not a frost-free freezer, which thaws on a regular basis. StuRat (talk) 18:36, 18 April 2012 (UTC)

See Seedbank#Optimal_storage_conditions. Yes, we preserve seeds by keeping them cold. Your home freezer may or may not be adequate for this purpose. Also, note that larger seeds tend to lose their viability more quickly than smaller seeds (especially in natural conditions, but also in artificial seedbanks). SemanticMantis (talk) 18:50, 18 April 2012 (UTC)

Also, we appreciate your questions, but please sign your posts by adding four tildes at the end, like this ~~~~ This helps us all keep track of who says what, and when :) SemanticMantis (talk) 19:34, 18 April 2012 (UTC)

I'm not sure that it would work with a conker, but you could always put one in your fridge and see. Alansplodge (talk) 19:40, 18 April 2012 (UTC)

Conker seeds don't survive very long, about three years or so under IDEAL laboratory conditions. Storing them in seed banks is a very big problem for professional breeders. They can't be frozen, and they die very quickly if they dry out (a couple of weeks in the open at room temperature, and they are definitely dead. They have to be stratified before they germinate, that is, kept in a moist, cold, but not freezing, environment for a few months before they will germinate, during which time they undergo what is called embryonic dormancy. Read about it here: http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=0CD4QFjAD&url=http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1046%2Fj.1469-8137.2003.00940.x%2Fpdf&ei=UDCPT73WFczDtAb93-ziCQ&usg=AFQjCNFDJr_LJ7VjeVtocGNk5PEbNJpPvQ&sig2=Gepbu4L6SwFEKKv7UFENJQ.

Conker breeding is a very big priority in northern Europe right now because they are an ideal city street and park tree, but are being attacked by an insect, the Horse-chestnut leaf miner. The insect lays it's eggs inside the leaves, and the larvae eat the leaves from the inside out. The trees look dreadful by the end of June. The insect came from southern Europe. Botanists hope to breed new hybrids that are resistant and able to grow in northern Europe by crossbreeding (hopefully resistant) varieties from sourthern Europe and elsewhere with the susceptible northern European varieties. Dominus Vobisdu (talk) 22:20, 18 April 2012 (UTC)

Just to clarify, the term is "seed vault". Applying electricity to a seed probably would not be beneficial to it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 00:47, 19 April 2012 (UTC)

do kids with progeria get very smart very fast

hi I just learned about the disease Progeria and it so sad that it break my heart. anyway, i would like to know if their brain ages very fast and if they become smart and wise like old people as they age to look like old people. ok so i know they dont have 70 years of experience and knowledge like a 70 year old has but still is it possible their brain develop very very fast and makes lots of neuron connections faster than a regular kid so they are super briliant? are they any famous adults with progeria. stephen hawking looks like he has it.--24.228.83.134 (talk) 19:29, 18 April 2012 (UTC)

Stephen Hawking has a form of Motor Neurone Disease and has recently celebrated his 70th birthday. I used to go to school with a kid with progeria, and I don't think they get clever at the same rate as their body ages. In fact, he was classed as having learning difficulties for whatever reason. --TammyMoet (talk) 19:38, 18 April 2012 (UTC)

The National Human Genome Research Institute says they possess "normal intelligence".[7] Clarityfiend (talk) 20:40, 18 April 2012 (UTC)

According to the wikipedia article, "Mental development is not adversely affected; in fact, intelligence tends to be above average.". It cites this article, but I don't have access to the full text, and it doesn't mention anything about intelligence in the abstract. 203.27.72.5 (talk) 20:56, 18 April 2012 (UTC)

The cited paper does indeed use that phrase, but it is itself citing "Cardiovascular abnormalities in progeria. Case report and review of the literature.", Archives of Pathology & Laboratory Medicine (1981), 105(7):384-6. Unfortunately, I cannot find that article online, and its abstract is similarly unhelpful. Someguy1221 (talk) 22:59, 18 April 2012 (UTC)

Painter and hip hop artist Leon Botha (1985-2011) has an article. Clarityfiend (talk) 03:07, 19 April 2012 (UTC)